var menuids = ["nav"]; //Enter id(s) of layersTree UL menus, separated by commas

function buildsubmenus_horizontal()
{
	for (var i = 0; i < menuids.length; i++)
	{
		var ultags = document.getElementById(menuids[i]).getElementsByTagName("ul");
		var l = getLeft(document.getElementById(menuids[i]));
		for (var t = 0; t < ultags.length; t++)
		{
			if (ultags[t].parentNode.parentNode.id == menuids[i])
			{ //if this is a first level submenu
				ultags[t].style.top = (- parseInt(ultags[t].offsetHeight, 10)) +"px"; //dynamically position first level submenus to be height of main menu item
				ultags[t].style.left = (getLeft(ultags[t].parentNode) - l) +"px";
			}
			else
			{ //else if this is a sub level menu (ul)
				ultags[t].style.left = ultags[t-1].getElementsByTagName("a")[0].offsetWidth +"px"; //position menu to the right of menu item that activated it
			}
			ultags[t].parentNode.onmouseover = function() {
				this.getElementsByTagName("ul")[0].style.visibility = "visible";
			}
			ultags[t].parentNode.onmouseout = function() {
				this.getElementsByTagName("ul")[0].style.visibility = "hidden";
			}
		}
	}
}

if (window.addEventListener)
{
	window.addEventListener("load", buildsubmenus_horizontal, false);
}
else if (window.attachEvent)
{
	window.attachEvent("onload", buildsubmenus_horizontal)
}

function getLeft(l)
{
	return (l.offsetParent) ? (l.offsetLeft + getLeft(l.offsetParent)) : (l.offsetLeft);
}